United States Defence Secretary Donald Rumsfeld has firmly dismissed criticism of the treatment of Taleban and al-Qaeda prisoners at Guantanamo Bay in Cuba.

At a Pentagon briefing, Mr Rumsfeld said all the 158 prisoners were being treated humanely.

Guantanamo Bay's climate is different than Afghanistan. To be in a eight-by-eight cell in beautiful sunny Guantanamo Bay, Cuba, is not inhumane treatment

Donald Rumsfeld, US Defence Secretary

His comments came as US human rights advocates launched a legal challenge against the detention of the prisoners, saying it violated international law and the United States constitution.

UK parliamentarians have also joined international criticism over the prisoners' treatment - spearheaded by human rights groups, including Amnesty International and the Red Cross.

These images spearheaded international criticism

The criticism grew after it emerged that the prisoners had been handcuffed, blindfolded and shackled; had had their beards shaved; were being forced to live in open-sided wire cells; and, in some cases, were sedated on the flight from Afghanistan.

The US has classed the detainees as "illegal combatants" rather than prisoners of war, denying them rights enshrined in the Geneva Convention on prisoners of war.

Humane

Mr Rumsfeld said the captives were being treated humanely and to suggest otherwise was "just plain false".

"What's going on down there is responsible, humane, legal, proper and consistent with the Geneva Convention," he said.